Itaconic acid deep eutectic solvent, preparation method and application thereof

Abstract

The application discloses itaconic acid deep eutectic solvent, a preparation method thereof and itaconic acid bio-based photocuring adhesive and itaconic acid photocuring antibacterial material prepared by using the itaconic acid deep eutectic solvent. The itaconic acid deep eutectic solvent is prepared by heating and mixing itaconic acid and a hydrogen bond acceptor, wherein the hydrogen bond acceptor is a glycidyl ether type epoxy compound, the molar ratio of the itaconic acid and the hydrogen bond acceptor is 1:(1-6), and the temperature of the heating and mixing is 60-75 DEG C. The application realizes the liquid state of itaconic acid at room temperature and solvent-free dissolution based on the deep eutectic principle, the prepared deep eutectic solvent can exist stably at room temperature for a long time, has the advantages of low viscosity and high active group content, and can be applied to the preparation of photocuring materials, such as photocuring ink, photocuring adhesive, photocuring coating, 3D printing material and the like.

Description

Technical Field

[0001] This invention belongs to the field of photocurable materials technology, and relates to an itaconic acid deep eutectic solvent, its preparation method and application. Background Technology

[0002] With the increasing global demand for carbon neutrality and growing public awareness of environmental pollution and green safety, green development in the chemical industry has become an inevitable trend. Deep eutectic solvents, due to their advantages such as good tunability, low vapor pressure, low flammability, and wide liquid range, are considered an emerging class of green solvents and have attracted widespread attention from researchers. Compared with traditional ionic liquids and organic solvents, deep eutectic solvents offer advantages such as low cost, biodegradability, environmental friendliness, and easier preparation under environmental conditions. They can be used as direct solvents, templates, or surfactants to dissolve transition metal oxides, form metal nanocomposites, and prepare polymer-based materials for various applications, playing multiple roles in material synthesis. Their environmental and economic sustainability and feasibility, unlike expensive and toxic ionic liquids or traditional solvents, have attracted considerable attention. Furthermore, the formulation of deep eutectic solvents preserves the complete structure between components, making them recyclable; the recovery of raw material components only requires breaking the hydrogen bonding interactions between the components in the solvent. On the other hand, unlike ionic liquid methods, deep eutectic solvents can perform simple polymer processing at very low temperatures with a conversion rate of 100%.

[0003] Currently, the selection of hydrogen bond donor and acceptor materials for deep eutectic solvents mainly focuses on the following four categories: (1) quaternary ammonium salts and metal halides; (2) quaternary ammonium salts and hydrated metal halides; (3) quaternary ammonium salts and hydrogen bond donors; and (4) metal halides and hydrogen bond donors.

[0004] Itaconic acid is considered a bio-based raw material with great application potential due to its structural similarity to acrylic acid. However, itaconic acid has a high melting point of 165-168℃ (lit.), making it difficult to dissolve by heating. Furthermore, itaconic acid has low solubility in organic solvents such as acetone and ethanol. A large amount of acetone needs to be added during the synthesis process. Acetone has a low boiling point and is toxic and flammable, posing a great threat to environmental protection and human safety during use. Therefore, there is an urgent need for a new process to solve the solubility problem of itaconic acid and reduce the use of toxic and harmful solvents.

[0005] Previous studies have successfully prepared deep eutectic solvents for itaconic acid using quaternary ammonium salts such as choline chloride and betaine as hydrogen bond acceptors. However, the high viscosity, low photosensitivity, and low functional group activity of these products have limited their application in solvents and chemical synthesis. For example, Maugeri Z et al. (DOI: 10.1039 / C1RA00630D) successfully prepared a deep eutectic solvent for itaconic acid using itaconic acid and choline chloride; however, the melting point Mp of this deep eutectic solvent was (57±3)℃. Although the melting point of itaconic acid has been significantly reduced, this solvent cannot exist in a stable liquid state at room temperature, thus limiting its further application. Therefore, it is necessary to find more promising hydrogen bond acceptors and solve the dissolution and application problems of itaconic acid based on the principle of deep eutectic solvent preparation. Summary of the Invention

[0006] The first objective of this invention is to provide a deep eutectic solvent for itaconic acid to solve at least one of the above-mentioned technical problems.

[0007] A second objective of the present invention is to provide a method for preparing the above-mentioned itaconic acid deep eutectic solvent, so as to solve at least one of the above-mentioned technical problems.

[0008] A third objective of the present invention is to provide the application of the above-mentioned itaconic acid deep eutectic solvent in the preparation of photocurable materials, so as to solve at least one of the above-mentioned technical problems.

[0009] According to one aspect of the present invention, a deep eutectic solvent for itaconic acid is provided, which is mainly prepared by heating and mixing itaconic acid and a hydrogen bond acceptor, wherein the hydrogen bond acceptor is a glycidyl ether type epoxy compound, the molar ratio of itaconic acid to the glycidyl ether type epoxy compound is 1:(1~6), and the heating and mixing temperature is 60~75°C.

[0010] This invention uses itaconic acid as a hydrogen bond donor (HBD) and a glycidyl ether-type epoxy compound as a hydrogen bond acceptor (HBA) to prepare a deep eutectic solvent for itaconic acid based on the deep eutectic principle. While retaining the chemical structure of itaconic acid, it lowers the melting point of solid itaconic acid, realizing the room temperature liquefaction and solvent-free dissolution of itaconic acid. This effectively solves the problems of high melting point of itaconic acid and high consumption of organic solvents in the synthesis and application processes.

[0011] In some embodiments, the glycidyl ether type epoxy compound may be selected from at least one of 2,3-epoxypropyltrimethylammonium chloride (CAS: 3033-77-0), glycidyl ether (CAS: 13236-02-7), tert-butyl glycidyl ether (CAS: 7665-72-7), o-tolyl glycidyl ether (CAS: 26447-14-3), neopentyl glycol diglycidyl ether (CAS: 17557-23-2), and butyl glycidyl ether (CAS: 17557-23-2).

[0012] Stability tests showed that the deep eutectic solvent is stable only under suitable hydrogen bond donor-acceptor ratios and preparation conditions. When the molar ratio of itaconic acid to hydrogen bond acceptor is 1:1, the heating temperature is 75℃, and the hydrogen bond acceptor is glycidyl ether, tert-butyl glycidyl ether, or o-tolyl glycidyl ether; or when the molar ratio of itaconic acid to hydrogen bond acceptor is 1:4, the heating temperature is 60℃, and the hydrogen bond acceptor is tert-butyl glycidyl ether or neopentyl glycol diglycidyl ether, the prepared deep eutectic solvent cannot remain stable at room temperature for an extended period. However, except for the above-mentioned cases, itaconic acid deep eutectic solvents prepared under other hydrogen bond donor-acceptor ratios and heating conditions are stable at room temperature.

[0013] According to another aspect of the present invention, a method for preparing the above-mentioned itaconic acid deep eutectic solvent is provided, comprising the following steps: removing water from itaconic acid, then mixing it with hydrogen bond acceptors, heating to 60~75°C, and stirring until the solid is completely melted to obtain the itaconic acid deep eutectic solvent.

[0014] The itaconic acid deep eutectic solvent provided by this invention has a melting point of less than 30°C and can exist stably in solution form at room temperature for a long time. Furthermore, the formation of the deep eutectic solvent is primarily driven by physical bonds; therefore, no chemical cross-linking occurs during solvent formation, meaning the chemical structure of the material remains intact. A large number of active groups in the raw material structure are retained, resulting in high curing activity and high cross-linking density, enabling the preparation of materials with high cross-linking density. Moreover, the deep eutectic solvent has excellent tunability, offering greater potential for the preparation of functional materials such as antibacterial agents. Simultaneously, the itaconic acid deep eutectic solvent provided by this invention exhibits good recyclability. While achieving room-temperature liquefaction of itaconic acid, it also preserves the structural integrity of individual components in the solvent; recovery only requires adding substances to break the physical bonds between components.

[0015] The itaconic acid deep eutectic solvent provided by this invention has the advantages of low viscosity and high content of active groups. Viscosity is an important indicator for evaluating deep eutectic solvents, and low-viscosity deep eutectic solvents can be widely used in the extraction and dissolution of substances. Furthermore, the itaconic acid deep eutectic solvent provided by this invention contains multiple active groups such as carboxylic acid groups, epoxy groups, and carbon-carbon double bonds, which allows it to be directly applied in chemical synthesis processes. Therefore, the itaconic acid deep eutectic solvent provided by this invention can be used to prepare photocurable materials, such as photocurable inks, photocurable adhesives, photocurable coatings, and 3D printing materials.

[0016] According to another aspect of the present invention, an itaconic acid bio-based photocurable adhesive is provided, which is mainly composed of an itaconic acid deep eutectic solvent and a composite photoinitiator provided by the present invention, wherein the mass ratio of the itaconic acid deep eutectic solvent to the composite photoinitiator is 100:(1~2), and the composite photoinitiator is composed of a free radical photoinitiator and a cationic photoinitiator in a mass ratio of (1~2):(1~2).

[0017] In some embodiments, the free radical photoinitiator may be selected from at least one of photoinitiator 1173, photoinitiator 184, photoinitiator TPO, and photoinitiator 907; the cationic photoinitiator may be selected from at least one of Easepi 6992, Easepi 6976, and Irgacure 250.

[0018] The itaconic acid deep eutectic solvent provided by this invention has low viscosity and good fluidity, which allows it to be spread on a variety of substrates (such as glass plates, acrylic plates, metal plates, wood, etc.) and wet the substrates well. As a result, the itaconic acid bio-based photocurable adhesive prepared by it has excellent adhesion to a variety of substrates, and its bonding performance is close to that of commercially available photocurable adhesives.

[0019] The itaconic acid deep eutectic solvent and composite photoinitiator provided in this invention are mixed in a specified ratio to obtain an itaconic acid bio-based photocurable adhesive. In use, the itaconic acid bio-based photocurable adhesive is coated onto a substrate, a light-transmitting material is placed over the adhesive layer, and photocuring is performed under ultraviolet light irradiation to achieve adhesion. The ultraviolet light source can be a UV point light source with a wavelength of 365-395 nm, and the curing time can be 30-120 seconds.

[0020] According to another aspect of the present invention, an itaconic acid photocurable antibacterial material is provided, comprising, by mass parts: 80-99 parts of the itaconic acid deep eutectic solvent provided by the present invention, 1-20 parts of the antibacterial agent and 1-2 parts of the composite photoinitiator; wherein the antibacterial agent may be selected from at least one of eugenol, vanillin, cinnamic acid and cinnamaldehyde; the composite photoinitiator is composed of a free radical photoinitiator and a cationic photoinitiator in a mass ratio of (1-2):(1-2).

[0021] In some embodiments, the free radical photoinitiator may be selected from at least one of photoinitiator 1173, photoinitiator 184, photoinitiator TPO, and photoinitiator 907; the cationic photoinitiator may be selected from at least one of Easepi 6992, Easepi 6976, and Irgacure 250.

[0022] The curing method of the itaconic acid photocurable antibacterial material of the present invention is photocuring, the light irradiation time is 0.1~5min, and the light source used is a UV point light source with a wavelength of 365~395nm.

[0023] The itaconic acid photocurable antibacterial material prepared by the present invention using itaconic acid deep eutectic solvent not only has good antibacterial properties, but also has stronger mechanical properties than the base material.

[0024] This invention utilizes hydrogen bonds formed between itaconic acid and glycidyl ether-type epoxy compounds to achieve room-temperature liquefaction of itaconic acid. Simultaneously, it leverages the carbon-carbon double bonds in the itaconic acid structure and the epoxy groups in the glycidyl ether-type epoxy compounds to achieve free radical-cationic and photo-thermal multi-curing. Photocurable materials are prepared using photoinduced thermal front-end polymerization technology, resulting in high raw material conversion rates, a simple preparation method, mild conditions, environmental friendliness and energy efficiency, stable product quality, and suitability for large-scale production. Attached Figure Description

[0025] Figure 1 The graph shows the stability of the itaconic acid deep eutectic solvent prepared in Examples 1-23 of this invention after being left at room temperature for 72 hours.

[0026] Figure 2 The diagram shows the shear rate-viscosity curves of the itaconic acid deep eutectic solvents prepared in Examples 7-10 and Example 15 of this invention, where S7-S10 represent the itaconic acid deep eutectic solvents prepared in Examples 7-10, and S15 represents the itaconic acid deep eutectic solvent prepared in Example 15.

[0027] Figure 3 This is a molecular electrostatic potential analysis diagram of the hydrogen bond acceptor glycidyl ether (HBA) and the hydrogen bond donor itaconic acid (HBD) in the itaconic acid deep eutectic solvent prepared in Example 15 of the present invention.

[0028] Figure 4 The diagram shows the 2D / 3D non-covalent interaction diagram and hydrogen bond formation site analysis diagram of the itaconic acid deep eutectic solvent hydrogen bond formation obtained in Example 15 of this invention.

[0029] Figure 5The following are chemical structure characterization diagrams of the itaconic acid deep eutectic solvents prepared in Examples 7-10 and Example 15 of this invention, wherein (a) is a gel permeation chromatogram of the deep eutectic solvent; (b) and (c) are characteristic peak shift diagrams of the Fourier transform infrared absorption spectra of the hydrogen bond donor itaconic acid and the deep eutectic solvent; (d) is a three-dimensional nuclear magnetic resonance (NMR) 1H spectrum of the deep eutectic solvent; (e) is a shifted NMR spectrum of the hydrogen bond acceptor; (f) is a shifted NMR spectrum of the hydrogen bond donor; AA represents itaconic acid, and D1-D5 represent the itaconic acid deep eutectic solvents prepared in Examples 7-10 and 15, respectively.

[0030] Figure 6 The bar charts show the shear strength of the itaconic acid bio-based photocurable adhesives prepared using itaconic acid deep eutectic solvent in Application Examples 1-5 and the commercially available photocurable adhesive in Application Example 6 on a substrate; wherein, D0 represents the commercially available photocurable adhesive in Application Example 6, and D1-D5 represent the itaconic acid bio-based photocurable adhesives prepared using itaconic acid deep eutectic solvent in Application Examples 1-5 respectively.

[0031] Figure 7-10 The figures are contact angle curves of the itaconic acid bio-based photocurable adhesives prepared using itaconic acid deep eutectic solvent in Application Examples 1-5 of the present invention with different substrate surfaces; wherein, D1-D5 sequentially represent the itaconic acid bio-based photocurable adhesives prepared using itaconic acid deep eutectic solvent in Application Examples 1-5.

[0032] Figure 11 The diagram shows the antibacterial properties of the itaconic acid photocurable materials prepared using itaconic acid deep eutectic solvent in Application Examples 7 and 12-20 of this invention; wherein, (a) is a characterization diagram of the antibacterial properties of the itaconic acid photocurable material against Staphylococcus aureus; (b) is a characterization diagram of the antibacterial properties of the itaconic acid photocurable material against Escherichia coli; D7 represents the itaconic acid photocurable material prepared using itaconic acid deep eutectic solvent in Application Example 7, and D12-D20 represent the itaconic acid photocurable antibacterial materials prepared using itaconic acid deep eutectic solvent in Application Examples 12-20 respectively.

[0033] Figure 12 The diagrams show the antibacterial properties of the itaconic acid photocurable materials prepared using itaconic acid deep eutectic solvent in Application Examples 21-29 of this invention; wherein, (a) is a characterization diagram of the antibacterial properties of the itaconic acid photocurable material against Staphylococcus aureus; (b) is a characterization diagram of the antibacterial properties of the itaconic acid photocurable material against Escherichia coli, and D21-29 sequentially represent the itaconic acid photocurable materials prepared using itaconic acid deep eutectic solvent in Application Examples 21-29.

[0034] Figure 13The graphs show the elongation at break versus tensile strength of the itaconic acid photocurable materials prepared using a deep eutectic solvent in Application Examples 7 and 12-20 of this invention; wherein, D7 represents the itaconic acid photocurable material prepared using a deep eutectic solvent in Application Example 7, and D12-D20 represent the itaconic acid photocurable antibacterial materials prepared using a deep eutectic solvent in Application Examples 12-20.

[0035] Figure 14 The above are the elongation at break-tensile strength curves of the itaconic acid photocurable materials prepared using the itaconic acid deep eutectic solvent in Application Examples 21-29 of the present invention. D21-29 respectively represent the itaconic acid photocurable materials prepared using the itaconic acid deep eutectic solvent in Application Examples 21-29.

[0036] Figure 15 The images show thermal imaging and front-end temperature detection curves of the photocuring process of the itaconic acid photocurable antibacterial materials prepared in Examples 12-16 of this invention; wherein, S12-S16 represent the itaconic acid photocurable antibacterial materials prepared using itaconic acid deep eutectic solvent in Examples 12-16. Detailed Implementation

[0037] The present invention will be further described in detail below with reference to the embodiments. The embodiments are for illustrative purposes only and do not limit the invention in any way. Unless otherwise specified, the raw materials and reagents used in the embodiments are conventional products that can be obtained commercially; experimental methods that do not specify specific conditions in the embodiments are generally performed under conventional conditions in the art or according to the conditions recommended by the manufacturer.

[0038] Example 1: Itaconic acid deep eutectic solvent

[0039] One molar amount of itaconic acid, dried to near-absence, was added to a reactor along with one molar amount of o-tolyl glycidyl ether. The mixture was heated to 75°C and stirred at 75°C until the solid was completely melted, forming a deep eutectic solvent for itaconic acid, thus obtaining liquefied itaconic acid. The stability of the obtained deep eutectic solvent was observed at room temperature.

[0040] Example 2 Itaconic acid deep eutectic solvent

[0041] One molar amount of itaconic acid, dried to near-absence, was added to a reactor along with one molar amount of tert-butyl glycidyl ether. The mixture was heated to 75°C and stirred at 75°C until the solid was completely melted, forming a deep eutectic solvent for itaconic acid, thus obtaining liquefied itaconic acid. The stability of the obtained deep eutectic solvent was observed at room temperature.

[0042] Example 3: Itaconic acid deep eutectic solvent

[0043] One molar amount of itaconic acid, dried to near-absence, was added to a reactor along with one molar amount of neopentyl glycol diglycidyl ether. The mixture was heated to 75°C and stirred at 75°C until the solid was completely melted, forming a deep eutectic solvent for itaconic acid, thus obtaining liquefied itaconic acid. The stability of the obtained deep eutectic solvent was observed at room temperature.

[0044] Example 4: Itaconic acid deep eutectic solvent

[0045] One molar amount of itaconic acid, dried to near-absence, was added to a reactor along with three molar amounts of o-tolyl glycidyl ether. The mixture was heated to 70°C and stirred at 70°C until the solid was completely melted, forming a deep eutectic solvent for itaconic acid, thus obtaining liquefied itaconic acid. The stability of the obtained deep eutectic solvent was observed at room temperature.

[0046] Example 5: Itaconic acid deep eutectic solvent

[0047] One molar amount of itaconic acid, dried to near-absence, was added to a reactor along with three molar amounts of butyl glycidyl ether. The mixture was heated to 70°C and stirred at 70°C until the solid was completely melted, forming a deep eutectic solvent for itaconic acid, thus obtaining liquefied itaconic acid. The stability of the obtained deep eutectic solvent was observed at room temperature.

[0048] Example 6: Itaconic acid deep eutectic solvent

[0049] One molar amount of itaconic acid, dried to near-absence, was added to a reactor along with three molar amounts of neopentyl glycol diglycidyl ether. The mixture was heated to 70°C and stirred at 70°C until the solid was completely melted, forming a deep eutectic solvent for itaconic acid, thus obtaining liquefied itaconic acid. The stability of the obtained deep eutectic solvent was observed at room temperature.

[0050] Example 7: Itaconic acid deep eutectic solvent

[0051] One molar amount of itaconic acid, dried to near-absence, was added to a reactor along with four molar amounts of o-tolyl glycidyl ether. The mixture was heated to 65°C and stirred at 65°C until the solid was completely melted, forming a deep eutectic solvent for itaconic acid, thus obtaining liquefied itaconic acid. The stability of the obtained deep eutectic solvent was observed at room temperature.

[0052] Example 8: Itaconic acid deep eutectic solvent

[0053] One molar amount of itaconic acid, dried to near-absence, was added to a reactor along with four molar amounts of butyl glycidyl ether. The mixture was heated to 65°C and stirred at 65°C until the solid was completely melted, forming a deep eutectic solvent for itaconic acid, thus obtaining liquefied itaconic acid. The stability of the obtained deep eutectic solvent was observed at room temperature.

[0054] Example 9: Itaconic acid deep eutectic solvent

[0055] One molar amount of itaconic acid, dried to near-absence, was added to a reactor along with four molar amounts of neopentyl glycol diglycidyl ether. The mixture was heated to 65°C and stirred at 65°C until the solid completely melted, forming a deep eutectic solvent for itaconic acid, thus obtaining liquefied itaconic acid. The stability of the obtained deep eutectic solvent was observed at room temperature.

[0056] Example 10 Itaconic acid deep eutectic solvent

[0057] One molar amount of itaconic acid, dried to near-absence, was added to a reactor along with four molar amounts of tert-butyl glycidyl ether. The mixture was heated to 65°C and stirred at 65°C until the solid was completely melted, forming a deep eutectic solvent for itaconic acid, thus obtaining liquefied itaconic acid. The stability of the obtained deep eutectic solvent was observed at room temperature.

[0058] Example 11 Itaconic acid deep eutectic solvent

[0059] One molar amount of itaconic acid, dried to near-absence, was added to a reactor along with five molar amounts of neopentyl glycol diglycidyl ether. The mixture was heated to 65°C and stirred at 65°C until the solid completely melted, forming a deep eutectic solvent for itaconic acid, thus obtaining liquefied itaconic acid. The stability of the obtained deep eutectic solvent was observed at room temperature.

[0060] Example 12 Itaconic acid deep eutectic solvent

[0061] One molar amount of itaconic acid, dried to near-absence, was added to a reactor along with six molar amounts of butyl glycidyl ether. The mixture was heated to 65°C and stirred at 65°C until the solid was completely melted, forming a deep eutectic solvent for itaconic acid, thus obtaining liquefied itaconic acid. The stability of the obtained deep eutectic solvent was observed at room temperature.

[0062] Example 13 Itaconic acid deep eutectic solvent

[0063] One molar amount of itaconic acid, dried to near-absence, was added to a reactor along with six molar amounts of neopentyl glycol diglycidyl ether. The mixture was heated to 65°C and stirred at 65°C until the solid completely melted, forming a deep eutectic solvent for itaconic acid, thus obtaining liquefied itaconic acid. The stability of the obtained deep eutectic solvent was observed at room temperature.

[0064] Example 14 Itaconic acid deep eutectic solvent

[0065] One molar amount of itaconic acid, dried to near-absence, was added to a reactor along with five molar amounts of glycidyl ether. The mixture was heated to 65°C and stirred at 65°C until the solid was completely melted, forming a deep eutectic solvent for itaconic acid, thus obtaining liquefied itaconic acid. The stability of the obtained deep eutectic solvent was observed at room temperature.

[0066] Example 15 Itaconic acid deep eutectic solvent

[0067] One molar amount of itaconic acid, dried to near-absence, was added to a reactor along with four molar amounts of glycidyl ether. The mixture was heated to 65°C and stirred at 65°C until the solid completely melted, forming a deep eutectic solvent for itaconic acid, thus obtaining liquefied itaconic acid. The stability of the obtained deep eutectic solvent was observed at room temperature.

[0068] Example 16 Itaconic acid deep eutectic solvent

[0069] One molar amount of itaconic acid, dried to near-absence, was added to a reactor along with three molar amounts of glycidyl ether. The mixture was heated to 70°C and stirred at 70°C until the solid was completely melted, forming a deep eutectic solvent for itaconic acid, thus obtaining liquefied itaconic acid. The stability of the obtained deep eutectic solvent was observed at room temperature.

[0070] Example 17 Itaconic acid deep eutectic solvent

[0071] One molar amount of itaconic acid, dried to near-absence, was added to a reactor along with two molar amounts of glycidyl ether. The mixture was heated to 70°C and stirred at 70°C until the solid was completely melted, forming a deep eutectic solvent for itaconic acid, thus obtaining liquefied itaconic acid. The stability of the obtained deep eutectic solvent was observed at room temperature.

[0072] Example 18 Itaconic acid deep eutectic solvent

[0073] One molar amount of itaconic acid, dried to near-absence, was added to a reactor along with one molar amount of glycidyl ether. The mixture was heated to 75°C and stirred at 75°C until the solid was completely melted, forming a deep eutectic solvent for itaconic acid, thus obtaining liquefied itaconic acid. The stability of the obtained deep eutectic solvent was observed at room temperature.

[0074] Example 19 Itaconic acid deep eutectic solvent

[0075] One molar amount of itaconic acid, dried to near-absence, was added to a reactor along with five molar amounts of glycidyl ether. The mixture was heated to 60°C and stirred at 60°C until the solid was completely melted, forming a deep eutectic solvent for itaconic acid, thus obtaining liquefied itaconic acid. The stability of the obtained deep eutectic solvent was observed at room temperature.

[0076] Example 20 Itaconic acid deep eutectic solvent

[0077] One molar amount of itaconic acid, dried to near-absence, was added to a reactor along with three molar amounts of glycidyl ether. The mixture was heated to 65°C and stirred at 65°C until the solid was completely melted, forming a deep eutectic solvent for itaconic acid, thus obtaining liquefied itaconic acid. The stability of the obtained deep eutectic solvent was observed at room temperature.

[0078] Example 21 Itaconic acid deep eutectic solvent

[0079] One molar amount of itaconic acid, dried to near-absence, was added to a reactor along with six molar amounts of glycidyl ether. The mixture was heated to 60°C and stirred at 60°C until the solid was completely melted, forming a deep eutectic solvent for itaconic acid, thus obtaining liquefied itaconic acid. The stability of the obtained deep eutectic solvent was observed at room temperature.

[0080] Example 22 Itaconic acid deep eutectic solvent

[0081] One molar amount of itaconic acid, dried to near-absence, was added to a reactor along with four molar amounts of tert-butyl glycidyl ether. The mixture was heated to 60°C and stirred at 60°C until the solid was completely melted, forming a deep eutectic solvent for itaconic acid, thus obtaining liquefied itaconic acid. The stability of the obtained deep eutectic solvent was observed at room temperature.

[0082] Example 23 Itaconic acid deep eutectic solvent

[0083] One molar amount of itaconic acid, dried to near-absence, was added to a reactor along with four molar amounts of neopentyl glycol diglycidyl ether. The mixture was heated to 60°C and stirred at 60°C until the solid was completely melted, forming a deep eutectic solvent for itaconic acid, thus obtaining liquefied itaconic acid. The stability of the obtained deep eutectic solvent was observed at room temperature.

[0084] Application Example 1: Itaconic acid bio-based light-curing adhesive

[0085] By weight, 100 parts of the itaconic acid deep eutectic solvent prepared in Example 6 and 1.5 parts of the composite photoinitiator were mixed evenly at room temperature to obtain an itaconic acid bio-based photocurable adhesive, wherein the composite photoinitiator was composed of photoinitiator 184 and Easepi 6992 in a mass ratio of 2:1.

[0086] In some embodiments, the above-mentioned itaconic acid bio-based photocurable adhesive can be used as follows: take an appropriate amount of itaconic acid bio-based photocurable adhesive and coat it onto a substrate, cover the adhesive layer with a light-transmitting material, and perform photocuring under a 365nm wavelength ultraviolet light source for 120s.

[0087] Application Example 2: Itaconic acid bio-based light-curing adhesive

[0088] By weight, 100 parts of the itaconic acid deep eutectic solvent prepared in Example 5 and 1 part of the composite photoinitiator were mixed evenly at room temperature to obtain an itaconic acid bio-based photocurable adhesive. The composite photoinitiator was composed of photoinitiator TPO and Easepi 6976 in a mass ratio of 2:1.

[0089] In some embodiments, the above-mentioned itaconic acid bio-based photocurable adhesive can be used as follows: take an appropriate amount of itaconic acid bio-based photocurable adhesive and coat it onto a substrate, select a light-transmitting material to cover the adhesive layer, and perform photocuring under a 395nm wavelength ultraviolet light source for 100s.

[0090] Application Example 3: Itaconic acid bio-based light-curing adhesive

[0091] By weight, 100 parts of the itaconic acid deep eutectic solvent prepared in Example 10 and 1.25 parts of the composite photoinitiator were mixed evenly at room temperature to obtain an itaconic acid bio-based photocurable adhesive, wherein the composite photoinitiator was composed of photoinitiator 1173 and Irgacure 250 in a mass ratio of 2:1.

[0092] In some embodiments, the above-mentioned itaconic acid bio-based photocurable adhesive can be used as follows: take an appropriate amount of itaconic acid bio-based photocurable adhesive and coat it onto a substrate, cover the adhesive layer with a light-transmitting material, and perform photocuring under a 365nm wavelength ultraviolet light source for 120s.

[0093] Application Example 4: Itaconic acid bio-based light-curing adhesive

[0094] By weight, 100 parts of the itaconic acid deep eutectic solvent prepared in Example 7 and 1.5 parts of the composite photoinitiator were mixed evenly at room temperature to obtain an itaconic acid bio-based photocurable adhesive, wherein the composite photoinitiator was composed of photoinitiator 907 and Easepi 6976 in a mass ratio of 1:1.

[0095] In some embodiments, the above-mentioned itaconic acid bio-based photocurable adhesive can be used as follows: take an appropriate amount of itaconic acid bio-based photocurable adhesive and coat it onto a substrate, cover the adhesive layer with a light-transmitting material, and perform photocuring under a 365nm wavelength ultraviolet light source for 90s.

[0096] Application Example 5: Itaconic acid bio-based light-curing adhesive

[0097] By weight, 100 parts of the itaconic acid deep eutectic solvent prepared in Example 19 and 1 part of the composite photoinitiator were mixed evenly at room temperature to obtain an itaconic acid bio-based photocurable adhesive, wherein the composite photoinitiator was composed of photoinitiator 1173 and Easepi 6992 in a mass ratio of 1:1.

[0098] In some embodiments, the above-mentioned itaconic acid bio-based photocurable adhesive can be used as follows: take an appropriate amount of itaconic acid bio-based photocurable adhesive and coat it onto a substrate, select a light-transmitting material to cover the adhesive layer, and perform photocuring under a 395nm wavelength ultraviolet light source for 100s.

[0099] Application Example 6: Commercially available adhesive 9307

[0100] The method of use is as follows: apply an appropriate amount of commercially available adhesive 9307 to the substrate, cover the adhesive layer with a light-transmitting material, and cure it under a 395nm wavelength ultraviolet light source for 100s.

[0101] Application Example 7: Itaconic acid photocurable material

[0102] Weigh 5g of the itaconic acid deep eutectic solvent prepared in Example 14, add 0.06g of the composite photoinitiator, and mix thoroughly to obtain the itaconic acid photocurable material; wherein, the composite initiator is composed of photoinitiator 1173 and Easepi 6992 in a mass ratio of 1:1.

[0103] In some embodiments, the above-mentioned itaconic acid bio-photocurable material can be used by pouring it into a mold and curing it for 120 seconds under a 365nm ultraviolet light source.

[0104] Application Example 8: Itaconic acid photocurable material

[0105] Weigh 5g of the itaconic acid deep eutectic solvent prepared in Example 15, add 0.08g of the composite photoinitiator, and mix thoroughly to obtain the itaconic acid photocurable material; wherein, the composite initiator is composed of photoinitiator 1173 and Easepi 6992 in a mass ratio of 1:1.

[0106] In some embodiments, the above-mentioned itaconic acid bio-photocurable material can be used by pouring it into a mold and curing it for 100 seconds under a 365nm ultraviolet light source.

[0107] Application Example 9: Itaconic acid photocurable material

[0108] Weigh 5g of the itaconic acid deep eutectic solvent prepared in Example 16, add 0.08g of composite photoinitiator and mix evenly to obtain itaconic acid photocurable material; wherein, the composite initiator is composed of photoinitiator 1173 and Easepi 6992 in a mass ratio of 1:1.

[0109] In some embodiments, the above-mentioned itaconic acid bio-photocurable material can be used by pouring it into a mold and curing it for 100 seconds under a 365nm ultraviolet light source.

[0110] Application Example 10: Itaconic acid photocurable material

[0111] Weigh 5g of the itaconic acid deep eutectic solvent prepared in Example 17, add 0.10g of composite photoinitiator and mix evenly to obtain itaconic acid photocurable material; wherein, the composite initiator is composed of photoinitiator 1173 and Easepi 6992 in a mass ratio of 1:1.

[0112] In some embodiments, the above-mentioned itaconic acid bio-photocurable material can be used by pouring it into a mold and curing it for 100 seconds under a 365nm ultraviolet light source.

[0113] Application Example 11: Itaconic acid photocurable material

[0114] Weigh 5g of the itaconic acid deep eutectic solvent prepared in Example 19, add 0.10g of composite photoinitiator and mix evenly to obtain itaconic acid photocurable material; wherein, the composite initiator is composed of photoinitiator 1173 and Easepi 6992 in a mass ratio of 1:1.

[0115] In some embodiments, the above-mentioned itaconic acid bio-photocurable material can be used by pouring it into a mold and curing it for 100 seconds under a 365nm ultraviolet light source.

[0116] Application Example 12: Itaconic acid photocurable material

[0117] Weigh 5g of the itaconic acid deep eutectic solvent prepared in Example 14, add 0.8g of eugenol and 0.06g of composite photoinitiator and mix evenly to obtain itaconic acid photocurable antibacterial material; wherein, the composite initiator is composed of photoinitiator 1173 and Easepi 6976 in a mass ratio of 2:1.

[0118] In some embodiments, the above-mentioned itaconic acid bio-photocurable antibacterial material can be used by pouring it into a mold and curing it for 120 seconds under a 365nm ultraviolet light source.

[0119] Application Example 13: Itaconic acid photocurable material

[0120] Weigh 5g of the itaconic acid deep eutectic solvent prepared in Example 14, add 1.0g of vanillin and 0.06g of composite initiator and mix evenly to obtain itaconic acid photocurable antibacterial material; wherein, the composite initiator is composed of photoinitiator 1173 and Easepi 6976 in a mass ratio of 2:1.

[0121] In some embodiments, the above-mentioned itaconic acid bio-photocurable antibacterial material can be used by pouring it into a mold and curing it for 120 seconds under a 365nm ultraviolet light source.

[0122] Application Example 14: Itaconic acid photocurable material

[0123] Weigh 5g of the itaconic acid deep eutectic solvent prepared in Example 14, add 1.0g of eugenol and 0.06g of composite initiator and mix evenly to obtain itaconic acid photocurable antibacterial material; wherein, the composite initiator is composed of photoinitiator 1173 and Easepi 6976 in a mass ratio of 2:1.

[0124] In some embodiments, the above-mentioned itaconic acid bio-photocurable antibacterial material can be used by pouring it into a mold and curing it for 120 seconds under a 365nm ultraviolet light source.

[0125] Application Example 15: Itaconic acid photocurable material

[0126] Weigh 5g of the itaconic acid deep eutectic solvent prepared in Example 14, add 0.6g of cinnamic acid and 0.06g of composite initiator and mix evenly to obtain itaconic acid photocurable antibacterial material; wherein, the composite initiator is composed of photoinitiator 1173 and Easepi 6976 in a mass ratio of 2:1.

[0127] In some embodiments, the above-mentioned itaconic acid bio-photocurable antibacterial material can be used by pouring it into a mold and curing it for 120 seconds under a 365nm ultraviolet light source.

[0128] Application Example 16: Itaconic acid photocurable material

[0129] Weigh 5g of the itaconic acid deep eutectic solvent prepared in Example 14, add 0.2g of cinnamaldehyde and 0.06g of composite initiator and mix evenly to obtain itaconic acid photocurable antibacterial material; wherein, the composite initiator is composed of photoinitiator 1173 and Easepi 6976 in a mass ratio of 2:1.

[0130] In some embodiments, the above-mentioned itaconic acid bio-photocurable antibacterial material can be used by pouring it into a mold and curing it for 120 seconds under a 365nm ultraviolet light source.

[0131] Application Example 17: Itaconic acid photocurable material

[0132] Weigh 5g of the itaconic acid deep eutectic solvent prepared in Example 14, add 0.8g of vanillin and 0.06g of composite initiator and mix evenly to obtain itaconic acid photocurable antibacterial material; wherein, the composite initiator is composed of photoinitiator 1173 and Easepi 6976 in a mass ratio of 2:1.

[0133] In some embodiments, the above-mentioned itaconic acid bio-photocurable antibacterial material can be used by pouring it into a mold and curing it for 120 seconds under a 365nm ultraviolet light source.

[0134] Application Example 18: Itaconic acid photocurable material

[0135] Weigh 5g of the itaconic acid deep eutectic solvent prepared in Example 14, add 0.4g of cinnamic acid, 0.2g of cinnamaldehyde and 0.06g of composite initiator and mix evenly to obtain itaconic acid photocurable antibacterial material; wherein, the composite initiator is composed of photoinitiator 1173 and Easepi 6976 in a mass ratio of 2:1.

[0136] In some embodiments, the above-mentioned itaconic acid bio-photocurable antibacterial material can be used by pouring it into a mold and curing it for 120 seconds under a 365nm ultraviolet light source.

[0137] Application Example 19: Itaconic acid photocurable material

[0138] Weigh 5g of the itaconic acid deep eutectic solvent prepared in Example 14, add 0.8g of eugenol, 0.2g of vanillin and 0.06g of composite initiator and mix evenly to obtain itaconic acid photocurable antibacterial material; wherein, the composite initiator is composed of photoinitiator 1173 and Easepi 6976 in a mass ratio of 2:1.

[0139] In some embodiments, the above-mentioned itaconic acid bio-photocurable antibacterial material can be used by pouring it into a mold and curing it for 120 seconds under a 365nm ultraviolet light source.

[0140] Application Example 20: Itaconic acid photocurable material

[0141] Weigh 5g of the itaconic acid deep eutectic solvent prepared in Example 14, add 0.4g of eugenol, 0.6g of cinnamic acid and 0.06g of composite initiator and mix evenly to obtain itaconic acid photocurable antibacterial material; wherein, the composite initiator is composed of photoinitiator 1173 and Easepi 6976 in a mass ratio of 2:1.

[0142] In some embodiments, the above-mentioned itaconic acid bio-photocurable antibacterial material can be used by pouring it into a mold and curing it for 120 seconds under a 365nm ultraviolet light source.

[0143] Application Example 21: Itaconic acid photocurable material

[0144] Weigh 5g of the itaconic acid deep eutectic solvent prepared in Example 5, add 0.06g of composite photoinitiator and mix evenly to obtain itaconic acid photocurable material; wherein, the composite initiator is composed of photoinitiator 1173 and Easepi 6992 in a mass ratio of 1:2.

[0145] In some embodiments, the above-mentioned itaconic acid bio-photocurable material can be used by pouring it into a mold and curing it for 60 seconds under a 365nm ultraviolet light source.

[0146] Application Example 22: Itaconic acid photocurable material

[0147] Weigh 5g of the itaconic acid deep eutectic solvent prepared in Example 5, add 0.2g of cinnamic acid and 0.06g of composite initiator and mix evenly to obtain itaconic acid photocurable antibacterial material; wherein, the composite initiator is composed of photoinitiator 1173 and Easepi 6992 in a mass ratio of 1:2.

[0148] In some embodiments, the above-mentioned itaconic acid bio-photocurable antibacterial material can be used by pouring it into a mold and curing it for 60 seconds under a 365nm ultraviolet light source.

[0149] Application Example 23: Itaconic acid photocurable material

[0150] Weigh 5g of the itaconic acid deep eutectic solvent prepared in Example 12, add 0.4g of eugenol, 0.4g of cinnamic acid and 0.06g of composite initiator and mix evenly to obtain itaconic acid photocurable antibacterial material; wherein, the composite initiator is composed of photoinitiator 1173 and Easepi 6992 in a mass ratio of 1:2.

[0151] In some embodiments, the above-mentioned itaconic acid bio-photocurable antibacterial material can be used by pouring it into a mold and curing it for 60 seconds under a 365nm ultraviolet light source.

[0152] Application Example 24: Itaconic acid photocurable material

[0153] Weigh 5g of the itaconic acid deep eutectic solvent prepared in Example 6, add 0.08g of composite photoinitiator and mix evenly to obtain itaconic acid photocurable material; wherein, the composite initiator is composed of photoinitiator 184 and Easepi 6992 in a mass ratio of 1:1.

[0154] In some embodiments, the above-mentioned itaconic acid bio-photocurable material can be used by pouring it into a mold and curing it for 90 seconds under a 395nm ultraviolet light source.

[0155] Application Example 25: Itaconic acid photocurable material

[0156] Weigh 5g of the itaconic acid deep eutectic solvent prepared in Example 6, add 0.8g of cinnamaldehyde and 0.08g of composite initiator and mix evenly to obtain itaconic acid photocurable antibacterial material; wherein, the composite initiator is composed of photoinitiator 184 and Easepi 6992 in a mass ratio of 1:1.

[0157] In some embodiments, the above-mentioned itaconic acid bio-photocurable antibacterial material can be used by pouring it into a mold and curing it for 90 seconds under a 395nm ultraviolet light source.

[0158] Application Example 26: Itaconic acid photocurable material

[0159] Weigh 5g of the itaconic acid deep eutectic solvent prepared in Example 11, add 0.2g of eugenol, 0.2g of vanillin and 0.08g of composite initiator and mix evenly to obtain itaconic acid photocurable antibacterial material; wherein, the composite initiator is composed of photoinitiator 184 and Easepi 6992 in a mass ratio of 1:1.

[0160] In some embodiments, the above-mentioned itaconic acid bio-photocurable antibacterial material can be used by pouring it into a mold and curing it for 90 seconds under a 395nm ultraviolet light source.

[0161] Application Example 27: Itaconic acid photocurable material

[0162] Weigh 5g of the itaconic acid deep eutectic solvent prepared in Example 7, add 0.10g of composite photoinitiator and mix evenly to obtain itaconic acid photocurable material; wherein, the composite initiator is composed of photoinitiator 1173 and Easepi 6976 in a mass ratio of 1:2.

[0163] In some embodiments, the above-mentioned itaconic acid bio-photocurable material can be used by pouring it into a mold and curing it for 120 seconds under a 395nm ultraviolet light source.

[0164] Application Example 28: Itaconic acid photocurable material

[0165] Weigh 5g of the itaconic acid deep eutectic solvent prepared in Example 7, add 0.8g of vanillin and 0.10g of composite initiator and mix evenly to obtain itaconic acid photocurable antibacterial material; wherein, the composite initiator is composed of photoinitiator 1173 and Easepi 6976 in a mass ratio of 1:2.

[0166] In some embodiments, the above-mentioned itaconic acid bio-photocurable antibacterial material can be used by pouring it into a mold and curing it for 120 seconds under a 365nm ultraviolet light source.

[0167] Application Example 29: Itaconic acid photocurable material

[0168] Weigh 5g of the itaconic acid deep eutectic solvent prepared in Example 4, add 0.2g of cinnamaldehyde, 0.2g of cinnamic acid and 0.10g of composite initiator and mix evenly to obtain itaconic acid photocurable antibacterial material; wherein, the composite initiator is composed of photoinitiator 1173 and Easepi 6976 in a mass ratio of 1:2.

[0169] In some embodiments, the above-mentioned itaconic acid bio-photocurable antibacterial material can be used by pouring it into a mold and curing it for 120 seconds under a 365nm ultraviolet light source.

[0170] Experimental Example 1

[0171] The itaconic acid deep eutectic solvents prepared in Examples 1-23 were placed at room temperature, and their state was observed to determine their stability. The results are as follows: Figure 1 As shown. The solvents obtained in Examples 1, 2, and 18 showed precipitation of the raw material components after being left at room temperature for 72 hours. Based on the formation mechanism of deep eutectic solvents, this is presumably due to an unsuitable ratio of hydrogen bond donor and acceptor groups in the solvent, making it difficult for the components in the solvent to exist stably in the solvent through intermolecular hydrogen bond interactions. The deep eutectic solvents obtained in Examples 22 and 23 also showed solid precipitation after being left for 72 hours, indicating that the heating temperature used in Examples 22 and 23 did not meet the preparation conditions for itaconic acid deep eutectic solvents. In summary, deep eutectic solvents can only exist stably under suitable hydrogen bond donor and acceptor ratios and preparation conditions. The itaconic acid deep eutectic solvents prepared in other examples can all exist stably at room temperature, indicating that the present invention has successfully achieved the room temperature liquefaction of itaconic acid based on the deep eutectic principle.

[0172] Furthermore, compared with the itaconic acid-choline chloride deep eutectic solvent (Mp: 57±3℃) in the prior art (DOI: 10.1039 / C1RA00630D), the itaconic acid deep eutectic solvent prepared by the present invention has a lower melting point (Mp: <30℃), which also means that the itaconic acid deep eutectic solvent prepared by the present invention is simpler and more convenient to use, without the need for heating.

[0173] Experimental Example 2

[0174] Viscosities of the itaconic acid deep eutectic solvents prepared in Examples 1-23 were tested. The rheological behavior of the itaconic acid deep eutectic solvents was determined using a rheometer with a plate assembly (MCR 502, Anton Paar, Austria). During the rheological analysis, the plates were spaced 0.5 mm apart (d=25 mm, spindle name: MCR-502SN82301309). The test temperature was constant at 25°C, and the shear rate range was 0.01 s⁻¹. -1 ~100s -1 The shear rate-viscosity curves of the itaconic acid deep eutectic solvents prepared in Examples 7-10 and Example 15 are shown below. Figure 2 As shown. Figure 2 The results show that the deep eutectic solvent formed by the epoxy group as a hydrogen bond acceptor group and the carboxylic acid group has a low viscosity and good flowability at room temperature.

[0175] Experimental Example 3

[0176] Taking Example 15 as an example, the ability of the epoxy group to form hydrogen bonds with the carboxylic acid group on itaconic acid was analyzed using chemical calculation analysis methods according to the method described in the literature (DOI: 10.1016 / j.carbpol.2022.119159). The results are as follows: Figure 3 and Figure 4 As shown.

[0177] Figure 3 The graph shows the molecular electrostatic potential (ESP) analysis of glycidyl ether (hydrogen bond acceptor) and itaconic acid (hydrogen bond donor). The results show that the oxygen atom on the epoxy group in glycidyl ether has the lowest ESP values, -34.18 kcal / mol, -32.34 kcal / mol, and -28.68 kcal / mol, respectively. The carboxyl group in itaconic acid has the highest ESP values, 52.96 kcal / mol and 53.61 kcal / mol, respectively. These calculations demonstrate that the epoxy group has the ability to act as a hydrogen bond acceptor and hydrogen bond donor to form hydrogen bonds.

[0178] This invention further analyzes the binding mode and hydrogen bond formation site between hydrogen bond acceptor and hydrogen bond acceptor molecules by calculating the non-co-interactions formed between hydrogen bond acceptors and hydrogen bond donors. Figure 4 The diagrams show the 2D / 3D non-covalent interactions and hydrogen bond formation sites of itaconic acid in deep eutectic solvents. The results indicate that the presence of multiple hydrogen bond donor and acceptor groups in the hydrogen bond donor-acceptor structure provides multiple hydrogen bond formation sites. Both carboxyl groups in the itaconic acid structure can form hydrogen bonds with the oxygen atoms on the glycidyl ether epoxy group. Furthermore, when itaconic acid forms two binding sites with glycidyl ether, a significantly larger and broader peak band is observed at the weak interaction site (blue area), indicating a stronger hydrogen bond interaction between the hydrogen bond donor and acceptor. The strongest hydrogen bond interaction occurs when three molecules of itaconic acid bind to one molecule of glycidyl ether. All these calculations and analyses demonstrate that the epoxy group has the ability to act as a hydrogen bond acceptor in the formulation of deep eutectic solvents, enabling the liquefaction of solid raw materials at room temperature.

[0179] Test Example 4

[0180] The itaconic acid deep eutectic solvents prepared in Examples 1-23 were subjected to molecular weight determination and chemical structure characterization. The itaconic acid deep eutectic solvents prepared in Examples 7-10 and Example 15 were used as examples, and the results are as follows: Figure 5 As shown.

[0181] GPC can be used to detect changes in the molecular weight of substances. Figure 5(a) The elution curves of the itaconic acid deep eutectic solvents prepared in Examples 7-10 and Example 15 show that no signal peaks of macromolecular substances appeared on the curves over a long period of time. This result is consistent with the viscosity test results, indicating that no significant chemical synthesis reaction to generate macromolecular polymers occurred during the heating and stirring process.

[0182] The chemical structure of the deep eutectic solvent for itaconic acid was analyzed. Unlike conventional chemical synthesis, the formation of deep eutectic solvents relies primarily on the physical interaction of intermolecular hydrogen bonds. Therefore, deep eutectic solvents are essentially mixtures of starting materials. The success of solvent preparation can be determined by detecting the integrity of the chemical structure of the starting materials. Figure 5 (b) and (c) are the infrared absorption spectra of the itaconic acid deep eutectic solvents prepared in Examples 7-10 and Example 15. Characteristic absorption peaks of carboxyl groups, carbon-carbon double bonds, and epoxy groups are clearly visible in the solvent. Combined with the 1H NMR spectrum of the solvent (Figure (d)), the multiplet at 6.11 ppm and the doublet at 5.95 ppm are absorption peaks of the carbon-carbon double bond in the hydrogen bond donor; 3.05 ppm and 2.71 ppm are characteristic peaks of the epoxy group in the hydrogen bond acceptor, indicating that the characteristic functional groups in the starting material are structurally complete. Furthermore, the reaction of carboxyl groups with epoxy groups produces ester bonds, and the signal peak of ester bonds usually appears at 4.3-4.5 ppm. However, as shown in the figure, no characteristic peak signal of ester groups appears in the 1H NMR spectrum of the solvent. This proves that the carboxyl groups and epoxy groups did not undergo cross-linking during heating and stirring. In addition, the formation of hydrogen bonds causes a shift in the infrared absorption spectrum and NMR absorption spectrum of the substance. Figure 5 As shown in (b), in the infrared absorption spectrum of itaconic acid, at 3028 cm⁻¹... -1 There is a distinct broad peak at [location missing], while the absorption peak of the carboxyl group in the deep eutectic solvents prepared in Examples 7-10 and Example 15 shows a significant shift, with peaks at 3477 cm⁻¹ and 3477 cm⁻¹, respectively. -1 3478cm -1 3466cm -1 3458cm -1 and 3465cm -1 .according to Figure 5 (c) The carbonyl absorption peak of itaconic acid is at 1703 cm⁻¹. -1 The carbonyl absorption peak in the deep eutectic solvents prepared in Examples 7-10 and Example 15 shifted to 1725 cm⁻¹. -1 1731cm -1 1723cm -1 1727cm -1 and 1722cm -1 Further verification was achieved through NMR absorption peak shift. Figure 5(e) is a schematic diagram of the NMR absorption peak shift of hydrogen bond acceptor and deep eutectic solvent. The NMR absorption peaks of hydrogen atoms on the epoxy group of hydrogen bond acceptor are 3.05 ppm and 2.71 ppm. It is obvious that the signal peak of epoxy group shifts to the higher field in deep eutectic solvent. Figure 5 (f) shows the NMR absorption peak shifts of the hydrogen bond donor and the deep eutectic solvent. The multiplets near 6.11 ppm and 5.95 ppm also show a significant shift to a lower field. This indicates the formation of intermolecular hydrogen bonds.

[0183] The above analysis shows that the chemical structures of the starting materials in the deep eutectic solvent prepared by this invention are complete and intermolecular hydrogen bonds are formed. The room temperature liquefaction of itaconic acid is mainly attributed to the intermolecular hydrogen bond interaction, which is different from the chemical grafting of itaconic acid using chemical synthesis methods disclosed in the prior art.

[0184] Experimental Example 5

[0185] The itaconic acid deep eutectic solvent prepared in Examples 1-23 was applied to the preparation of bio-based UV-curable adhesives. Shear strength tests were performed on the bio-based UV-curable adhesives prepared according to Examples 1-5 and Application Example 6 of ASTM F2255-03, "Tension-Shear Test Method for the Strength of Tissue Adhesives". The UV-cured samples were tested at room temperature using a universal testing machine (Model 1185, Instron, USA) at a crosshead speed of 5 mm / min. The adhesion strength of the prepared bio-based UV-curable adhesives is shown in the results below. Figure 6 As shown.

[0186] The results show that the itaconic acid bio-based UV-curable adhesive prepared using the itaconic acid deep eutectic solvent of this invention exhibits excellent adhesion properties. In some application examples, the shear strength of the adhesives prepared on PVC, aluminum, and wood panels is close to that of commercially available UV-curable adhesives.

[0187] Experimental Example 6

[0188] Corresponding to Use Cases 1-5 and Application Example 6, the contact angle of the itaconic acid bio-based UV-curable adhesive on the substrate surface was tested before curing to determine the spreading and wetting ability of the prepared adhesive on different substrates. The results are as follows: Figure 7-10 As shown in the figure, the results indicate that the prepared colloid forms contact angles between 0 and 30° on PVC, aluminum, and wood surfaces, completely wetting the substrate. This also demonstrates that the itaconic acid bio-based photocurable adhesive prepared using the prepared itaconic acid deep eutectic solvent can meet the application requirements of adhesives.

[0189] Experimental Example 7

[0190] The itaconic acid deep eutectic solvent prepared in Examples 1-23 was applied to the preparation of bio-based photocurable functional materials, specifically, to the preparation of photocurable antibacterial materials. The antibacterial activity of samples of itaconic acid photocurable materials prepared in Examples 7 and 12-29 after UV curing was determined. The inhibition zone method was used to study the antibacterial activity of the cured materials against *Escherichia coli* and *Staphylococcus aureus*. A 50-fold dilution of bacterial suspension was prepared and incubated at 37°C and humidity for 24 hours. 300 μL of the bacterial dilution was evenly spread onto a 15 cm diameter agar plate containing nutrients. A 7.5 mm diameter UV-cured sample was placed on the agar plate using a direct contact method. All plates were incubated at 37°C for 24 hours. The inhibition zone area of ​​each cured material was measured using precision calipers. All samples were tested three times, and the average value was taken.

[0191] Figure 11 (a) The inhibitory effect of the itaconic acid photocurable antibacterial materials prepared in Application Examples 7 and 12-20 on Staphylococcus aureus. Figure 11 (b) The inhibitory effect of Application Examples 7 and 12-20 on Escherichia coli. The itaconic acid photocurable material prepared in Application Example 7 served as a control. It can be seen that the itaconic acid photocurable antibacterial materials prepared in Application Examples 12-20 all showed significant inhibition bands against Escherichia coli and Staphylococcus aureus, exceeding their contact area. The diameters of the inhibition bands against Escherichia coli and Staphylococcus aureus reached a maximum of 43.2 mm and 38.0 mm, respectively. In contrast, only the area covered by the material in Application Example 7 achieved an antibacterial effect.

[0192] Figure 12 (a) The inhibitory effect of the itaconic acid photocurable materials prepared in Examples 21-29 on Staphylococcus aureus. Figure 12 (b) The inhibitory effect of the itaconic acid photocurable materials prepared in Application Examples 21-29 on Escherichia coli. It can be seen that the materials prepared in Application Examples 21, 24 and 27 without the addition of antibacterial agents only have an antibacterial effect on the area they cover, while the other application examples all show better antibacterial effects.

[0193] The above results demonstrate that the introduction of antibacterial agents gives the material good antibacterial activity against both *Escherichia coli* and *Staphylococcus aureus*. On one hand, the introduced eugenol, cinnamic acid, and other compounds contain carbon-carbon double bonds and carboxylic acid groups. These groups can cross-link with the chemical groups of the components in the itaconic acid deep eutectic solvent during photocuring, thereby grafting antibacterial substances into the material. On the other hand, antibacterial agents such as cinnamaldehyde and vanillin are embedded in a tight cross-linked network during component curing, thus enabling the material to also exhibit antibacterial properties.

[0194] Experimental Example 8

[0195] Following ASTM D638-03, the tensile mechanical properties of UV-cured itaconic acid antibacterial materials prepared using Example 7 and Application Example 12-29 of a Shimadzu AGS-X1kN electronic universal testing machine were tested. All specimens measured 30.0 mm (L) × 10.0 mm (W) × 0.5 mm (T) and were subjected to a tensile speed of 10 mm / min. -1 For accuracy, all samples were tested three times. The results are as follows: Figure 13 and Figure 14 As shown, some products, after the introduction of antibacterial agents, not only achieved excellent antibacterial properties but also improved mechanical properties. For example... Figure 13 As shown, the tensile strength of the photocurable material prepared using method 7 after photocuring is 29.03 MPa, while the tensile strength of the photocurable material prepared by adding an antibacterial agent can reach up to 61.66 MPa after photocuring. (Summary) Figure 13-14 The results showed that the introduction of eugenol as an antibacterial agent could enhance the mechanical properties of the material, while antibacterial agents such as vanillin and cinnamaldehyde, mainly existing in the cross-linked network, might affect the mechanical properties of the material to some extent. This is because the introduction of antibacterial agents with carbon-carbon double bonds and carboxylic acid groups increased the content of active groups in the composition, resulting in a denser cross-linked network during photocuring.

[0196] Experimental Example 9

[0197] Thermal imaging and temperature detection were performed on the itaconic acid photocurable antibacterial material prepared according to examples 12-16 during the photocuring process. The results are as follows: Figure 10 As shown. Under the initiation of a free radical photoinitiator, the carbon-carbon double bonds in components such as itaconic acid and eugenol undergo free radical curing. During curing, a large amount of heat is released, providing energy to the monomers in the un-illuminated areas, thereby initiating crosslinking of unpolymerized monomers. Furthermore, the large amount of energy released during group polymerization allows the material's front-end temperature to reach up to 178°C, a temperature sufficient to initiate the reaction between carboxylic acid groups and epoxy groups. Thirdly, a large number of epoxy groups in the composition can also polymerize under the action of a cationic initiator. Cationic polymerization has post-curing properties, allowing uncrosslinked monomers to continue crosslinking after the material is removed from the light source.

[0198] Therefore, this invention utilizes front-end polymerization propagation technology to achieve high conversion rates of deep eutectic solvents and energy-saving, rapid preparation of cured materials.

[0199] The above descriptions are merely some embodiments of the present invention. Those skilled in the art can make various modifications and improvements without departing from the inventive concept of the present invention, and these all fall within the scope of protection of the present invention.

Claims

1. A deep eutectic solvent for itaconic acid, mainly prepared by heating and mixing itaconic acid and hydrogen bond acceptor, characterized in that... The hydrogen bond acceptor is a glycidyl ether type epoxy compound, the molar ratio of itaconic acid to hydrogen bond acceptor is 1:(1~6), and the heating and mixing temperature is 60~75℃; The hydrogen bond acceptor is selected from at least one of 2,3-epoxypropyltrimethylammonium chloride, glycidyl ether, tert-butyl glycidyl ether, o-tolyl glycidyl ether, neopentyl glycol diglycidyl ether, and butyl glycidyl ether; wherein, when the molar ratio of itaconic acid to the hydrogen bond acceptor is 1:1 and the heating temperature is 75°C, the hydrogen bond acceptor is not glycidyl ether, tert-butyl glycidyl ether, or o-tolyl glycidyl ether; when the molar ratio of itaconic acid to the hydrogen bond acceptor is 1:4 and the heating temperature is 60°C, the hydrogen bond acceptor is not tert-butyl glycidyl ether or neopentyl glycol diglycidyl ether.

2. The method for preparing the itaconic acid deep eutectic solvent according to claim 1, characterized in that, The process includes the following steps: removing water from itaconic acid, then mixing it with hydrogen bond acceptors, heating to 60-75°C, and stirring until the solid is completely melted to obtain a deep eutectic solvent for itaconic acid.

3. The application of the itaconic acid deep eutectic solvent according to claim 1 in the preparation of photocurable materials.

4. The application according to claim 3, characterized in that, The photocurable material is selected from at least one of photocurable inks, photocurable adhesives, photocurable coatings, and 3D printing materials.

5. Itaconic acid bio-based light-curing adhesive, characterized in that, It is mainly composed of the itaconic acid deep eutectic solvent and the composite photoinitiator as described in claim 1, wherein the mass ratio of the itaconic acid deep eutectic solvent to the composite photoinitiator is 100:(1~2), and the composite photoinitiator is composed of a free radical photoinitiator and a cationic photoinitiator in a mass ratio of (1~2):(1~2).

6. The itaconic acid bio-based photocurable adhesive according to claim 5, characterized in that, The free radical photoinitiator is selected from at least one of photoinitiator 1173, photoinitiator 184, photoinitiator TPO, and photoinitiator 907; the cationic photoinitiator is selected from at least one of Easepi 6992, Easepi 6976, and Irgacure 250.

7. Itaconic acid photocurable antibacterial material, characterized in that, The product comprises, by mass parts: 80-99 parts of the itaconic acid deep eutectic solvent as described in claim 1, 1-20 parts of the antibacterial agent, and 1-2 parts of the composite photoinitiator; wherein the antibacterial agent is selected from at least one of eugenol, vanillin, cinnamic acid, and cinnamaldehyde; and the composite photoinitiator is composed of a free radical photoinitiator and a cationic photoinitiator in a mass ratio of (1-2):(1-2).

8. The itaconic acid photocurable antibacterial material according to claim 7, characterized in that, The free radical photoinitiator is selected from at least one of photoinitiator 1173, photoinitiator 184, photoinitiator TPO, and photoinitiator 907; the cationic photoinitiator is selected from at least one of Easepi 6992, Easepi 6976, and Irgacure 250.

9. The itaconic acid photocurable antibacterial material according to claim 7 or 8, characterized in that, Its curing method is photocuring, the light exposure time is 0.1~5min, and the light source used is a UV point light source with a wavelength of 365~395nm.

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